Article: Direction 21 Validation under the Plenary Powers of the generic names Bubo Dumeril, 1806, Coturnix Bonnaterre, 1790, Egretta Forster, 1817, and Oriolus Linnaeus, 1766 (class Aves), by the suppression of older Homonyms published by Brisson in 1760 (validation of four erroneous entries on the Official List of Generic Names in Zoology made by the ruling given in Opinion 67)